E-BIST: enhanced test-per-clock BIST architecture

A new enhanced built-in self-test (E-BIST) architecture, that is suitable for a test-per-clock scheme, is proposed. The E-BIST architecture is based on STUMPS (Self-Test Using MISR and Parallel Shift-register sequence generators), which uses a linear feedback shift register (LFSR) as the test generator, a multiple-input shift register (MISR) as the response compactor and shift register latch (SRL) channels as multiple scan paths. In E-BIST, a degenerate MISR structure is used for every SRL channel; this offers reduced area overheads and has less impact on performance than the STUMPS technique. It is also shown that the masking probability of the proposed SRL channel structure is 2^1-(N+L), where N is the number of test patterns and L is the length of the SRL channel. The results of experiments on ISCAS 89 (International Symposium on Circuits And Systems 1989) benchmark circuits show that this architecture is also suitable for robustly detecting path delay faults, with improved fault coverage, when the Hamming distance of the data in the SRL channel is considered